Liquid Crystal Fringe Pattern Generator for Miniaturized Profilometry
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Solution Overview
Problem
Current three-dimensional surface profilometers face challenges in miniaturization and commercialization due to the use of expensive and bulky optical components, such as digital micro-mirror devices, acousto-optical modulators, and spatial light modulators, which hinder their miniaturization and widespread adoption.
Innovation Solution
A dynamic fringe pattern generating apparatus using a liquid crystal layer with a slit array, where the period and phase of the fringe pattern are controlled by applying voltage, allowing for miniaturization without mechanical driving, utilizing a modulation characteristic of the effective refractive index to adjust spatial frequency and phase shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical components such as digital micro-mirror device, acousto-optical modulator, and spatial light modulator are used to generate fringe patterns, then the measurement performance is improved, but the device size and cost increase significantly
Solution Approach 1:
The patent replaces bulky mechanical optical components (DMD, AOM, SLM) with a micro-scale liquid crystal device that uses electrical field control instead of mechanical movement or complex optical paths. The liquid crystal layer modulates light phase and intensity through voltage application, eliminating the need for large mechanical actuators and optical assemblies.
Solution Approach 2:
The invention changes the control parameter from mechanical positioning or optical path length adjustment to electrical voltage control. By applying different voltages to the liquid crystal device, the fringe pattern parameters (phase, spatial frequency) are dynamically adjusted, achieving the same functionality as complex optical systems but with miniaturized dimensions.
2Measurement precision
If traditional optical components are used for fringe pattern generation, then the measurement accuracy is maintained, but the device complexity and cost increase
Solution Approach 1:
The patent merges multiple functions (fringe pattern generation, phase shifting, spatial frequency modulation) into a single liquid crystal device. Instead of requiring separate components for each function, the liquid crystal layer performs all modulations through integrated electrical control, significantly simplifying the overall system architecture.
Solution Approach 2:
The liquid crystal device serves multiple purposes: it generates fringe patterns, controls phase shifts, and modulates spatial frequency simultaneously through a single component. This multi-functional approach replaces what would traditionally require multiple specialized optical components, reducing both complexity and cost.
3Manufacturing precision
If mechanical driving is used to change fringe pattern parameters, then the control precision is achieved, but the device size and moving parts increase
Solution Approach 1:
The invention replaces mechanical driving mechanisms with electrical field control. The liquid crystal molecules reorient in response to applied voltages, enabling precise control of fringe pattern parameters without any moving parts. This electro-optic control mechanism achieves high precision while maintaining a compact, static device structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus achieves miniaturization to dimensions of 5×5 mm or less, reducing the size by a factor of 10 compared to traditional systems, enabling the creation of a compact three-dimensional surface profilometer with improved performance and cost-effectiveness.
Implementation Method 1
utilizing a modulation characteristic of an effective refractive index according to the applied voltage
Implementation Method 2
capable of simultaneously implementing a shifting characteristic and a period changing characteristic of a fringe pattern by only switching a voltage
Implementation Method 3
A dynamic fringe pattern generating apparatus using liquid crystal and method thereof... capable of changing a period of coherency of light incident on a multiple aligned liquid crystal sample by using a slit array
Data Source
AI summary
The dynamic fringe pattern generating apparatus includes a liquid crystal layer including a first area and a second area, a lower layer and an upper layer. The upper layer includes a slit array layer where a micro-slit array including a common slit and a plurality of selection slits are formed and an upper transparent electrode layer where a reference electrode and a plurality of selection electrodes are formed. In the dynamic fringe pattern generating apparatus, different fringe patterns are phase-shifted by sequentially controlling a voltage applied to the reference electrode and to the selection electrodes.